Cleaning compositions are well known in the art. Such compositions generally comprise a number of active components that provide the cleaning function of the composition. When selecting components of the composition, it is therefore preferred that the components are stable in the composition so as not to lose cleaning effectiveness. In certain instances however, some ingredients of a cleaning composition for example oxidising agents can decompose leading to a reduction in the concentration of oxidising agent over time and consequently to the reduction of the cleaning and whitening performance of the composition.
Cleaning compositions can also comprise, in addition to the oxidising agent, a number of other components that provide additional cleaning and whitening performance benefits. When selecting components of the composition, it is preferred that the components are stable in the composition, i.e., do not react with the oxidising agent, further reducing the concentration of oxidising agent in the composition. In certain instances however, the reaction or interaction of components of the composition with the oxidising agent is inevitable. As a consequence of this, the premature decomposition of the oxidising agent and the other actives present in the composition occurs, leading to the reduction of the cleaning and/or whiteness effectiveness of the composition.
Although not wishing to be bound by theory, it is believed that decomposition of the oxidising agent and the interaction or reaction of the different ingredients of the composition with the oxidising agent can proceed via one electron and/or two electron chemistry. One electron chemistry reactions are initiated by the formation of radicals from the parent oxidising agent. Generally, the radicals formed are more reactive and better oxidising species than the parent and thus accelerate the decomposition kinetics of the oxidising agents and its reaction or interaction with the other actives ingredients present in the composition. Thereby enhancing the decomposition of the oxidising agent and the other actives ingredients. For example, where brighteners are components of the composition, decomposition thereof can be initiated by one and/or two electron processes, resulting in the loss or decreased of whiteness performance benefit, normally expected when incorporating a brightener. The brightener oxidation via one electron processes is believed to proceed faster than the two electron oxidation. To improve the compatibility of the oxidising agent with the other actives, it is therefore important to reduce, slow down or completely suppress one electron oxidation chemistry reactions.
The Applicant has thus now surprisingly found that this problem is solved by formulating a liquid bleaching composition according to the present invention. EP-A-558345 discloses hypochlorite-containing compositions comprising a source of strong alkalinity, a pH buffering means (silicate/carbonate) and radical scavengers. The radical scavengers of the present invention are not disclosed therein. Furthermore, it has been found that compositions of the present invention are stable on storage and provide improved whiteness and cleaning performance in any laundry application even on ageing of the composition, i.e. when used after prolonged periods of storage, as compared to the whiteness and cleaning performance delivered by the same composition under the same conditions but without any radical scavenger. More particularly, it has been found that the stability of the oxidising agent and/or the other actives ingredients (where present), are improved when the radical scavenger of the present invention is present versus when it is not.
A further advantage of the compositions of the present invention is that they are suitable for the cleaning of different types of fabrics including natural fabrics (e.g., fabrics made of cotton, viscose, linen, silk and wool), synthetic fabrics such as those made of polymeric fibers of synthetic origin as well as those made of both natural and synthetic fibers.
Yet, another advantage of the liquid bleaching compositions of the present invention is that said bleaching compositions are suitable for various laundry cleaning applications both when used in diluted conditions, e.g. as a detergent additive of a fully formulated laundry detergent composition, and when used in neat condition, e.g. as a liquid pretreater (spotter).